King cobra (Ophiophagus hannah)

The king cobra is classified as Vulnerable (VU) on the IUCN Red List (1) and is listed on Appendix II of CITES (3).

The longest of all living venomous snakes, the magnificent king cobra (Ophiophagus hannah) has been the inspiration for a variety of myths and legends within its native range (3) (4). This species is not a true cobra of the genusNaja, and instead belongs to a unique genusOphiophagus, whose scientific name derives from the Greek for “snake-eating”, in reference to its dietary habits (5).

The head is broad and flattened (2), while the neck features a narrow hood, which can be extended when individuals feel threatened (4). The body colour is typically tan, olive-brown or black, and may be marked with white or yellow chevrons at the anterior of the body, which become straight bands towards the rear (2) (5). These bands usually fade with age, and may disappear altogether, although some adults exhibit them throughout life (5).

In contrast to the normal hissing sound produced by most snake species in response to threats, the king cobra makes a distinctive growl, which emanates from the throat and deepens as the snake grows (6).

The king cobra has a large range, extending from India, east to Bangladesh, Myanmar, Cambodia, southern China, Laos, Thailand, Vietnam, Malaysia, Indonesia and the Philippines (5).

Predominantly a forest-dwelling species, the king cobra occurs in rainforest, bamboo thickets and mangrove swamps, as well as other habitats with dense undergrowth and heavy rainfall (3) (7). It is known to occur from sea level to mountainous regions, at elevations of over 2,000 metres (3).

Active by day, the agile king cobra is capable of moving swiftly along the ground and through trees or water while searching for prey (2) (4). This species’ diet consists almost exclusively of snakes, the majority of which are non-venomous species, such as small pythons and rat snakes, although highly venomous species, such as cobras, kraits and even other king cobras, are also taken (7). The king cobra is also known to feed upon monitor lizards and take eggs on occasion (7) (8). Prey is located by smell and sight, and is actively pursued. When in range, its victim is dispatched with a rapid strike, injecting a large quantity of venom, which affects the nervous system and causes respiratory failure (2) (7).

While the king cobra’s venom is not as toxic as that of some highly venomous species, the sheer volume produced in a single bite is enough to kill 20 to 30 adult humans or a fully-grown Asian elephant (3) (8). Nevertheless, as this species is generally non-aggressive and occupies deep forest, bites to humans and the resulting fatalities are rare (2).

In response to threats, when unable to escape, the king cobra gives a dramatic display, in which the front third of the body is lifted off the ground, reaching a height of up to 1.5 metres. The narrow hood is also erected, a growling hiss is produced, and downward strikes are made, although it rarely attempts to bite (4) (9).

From January to March male king cobras seek out a mate by following chemical pheromone signals released by the females. Once located, the male employs courtship behaviours such as rubbing the head along the female’s body, which may develop into butting and nudging actions if the female shows reticence to mate. If other males are present, they may compete for the female by wrestling and attempting to push each other's head to the ground. During mating the male and the female’s bodies intertwine, and remain in this position for several hours (7).

The female produces a clutch of 20 to 50 eggs, which are laid in April, May or June, and deposited within a nest of twigs, leaves and other vegetation. The nest comprises a lower chamber for the eggs, which is covered over with leaf-litter, and an upper chamber on top, in which the female resides, guarding the eggs from predators and trampling. Such a complex nest is unique among snakes, and is considered to be a sign that the king cobra may be one of the most intelligent snake species (7). The eggs, which are incubated by the heat of the rotting vegetation, take between 60 and 90 days to hatch, and just prior to hatching the female abandons the nest, ceasing all parental care (7) (9).

The newborn cobras measure around 35 centimetres at birth, and already possess venom as toxic as the adult’s. Nevertheless, they are preyed upon by civets, mongooses, giant centipedes and army ants until they are several months old (7).

Historically, the king cobra was respected and even revered by some indigenous peoples within its range. Today, however, new generations are less tolerant of living alongside dangerous species, which has led to persecution. Another significant threat to this species is deforestation, which is claiming large tracts of its rainforest habitat to supply timber and to create space for agricultural land and expanding human settlements (10).

The king cobra is also harvested for its meat, skin and bile which are used in traditional medicine (7).

The king cobra is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES) which controls trade through the use of permits and maximum export quotas (3).

The most significant effort to conserve this species has been the establishment of the Agumbe Rainforest Research Station in the mountainous, biodiverse rainforests of the Western Ghats region of southern India. Founded by herpetologist Rom Whitaker and funded by the Whitley Fund for Nature, the station is working to promote conservation of the region’s rainforest, using the king cobra as its flagship species. The station provides a base for research into this species’ biology, which can be used to inform conservation action, involving participation by local Non-Governmental Organisations, as well as educational programmes in local schools (7) (10).

Authenticated (14/10/11) by Olivier S.G. Pauwels, Research Associate at the Royal Belgian Institute for Natural Sciences, Brussels, Belgium. http://www.pauwelsolivier.com/

Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Incubate: to keep eggs warm so that development is possible.

Pheromone: a chemical produced by an animal, which stimulates a behavioural or physiological response by another member of the same species.